1,760 research outputs found
On the experimental verification of quantum complexity in linear optics
The first quantum technologies to solve computational problems that are
beyond the capabilities of classical computers are likely to be devices that
exploit characteristics inherent to a particular physical system, to tackle a
bespoke problem suited to those characteristics. Evidence implies that the
detection of ensembles of photons, which have propagated through a linear
optical circuit, is equivalent to sampling from a probability distribution that
is intractable to classical simulation. However, it is probable that the
complexity of this type of sampling problem means that its solution is
classically unverifiable within a feasible number of trials, and the task of
establishing correct operation becomes one of gathering sufficiently convincing
circumstantial evidence. Here, we develop scalable methods to experimentally
establish correct operation for this class of sampling algorithm, which we
implement with two different types of optical circuits for 3, 4, and 5 photons,
on Hilbert spaces of up to 50,000 dimensions. With only a small number of
trials, we establish a confidence >99% that we are not sampling from a uniform
distribution or a classical distribution, and we demonstrate a unitary specific
witness that functions robustly for small amounts of data. Like the algorithmic
operations they endorse, our methods exploit the characteristics native to the
quantum system in question. Here we observe and make an application of a
"bosonic clouding" phenomenon, interesting in its own right, where photons are
found in local groups of modes superposed across two locations. Our broad
approach is likely to be practical for all architectures for quantum
technologies where formal verification methods for quantum algorithms are
either intractable or unknown.Comment: Comments welcom
Clinical, radiologic, pathologic, and molecular characteristics of long-term survivors of diffuse intrinsic pontine glioma (DIPG): a collaborative report from the International and European Society for Pediatric Oncology DIPG registries
Purpose Diffuse intrinsic pontine glioma (DIPG) is a brainstem malignancy with a median survival of < 1 year. The International and European Society for Pediatric Oncology DIPG Registries collaborated to compare clinical, radiologic, and histomolecular characteristics between short-term survivors (STSs) and long-term survivors (LTSs). Materials and Methods Data abstracted from registry databases included patients from North America, Australia, Germany, Austria, Switzerland, the Netherlands, Italy, France, the United Kingdom, and Croatia. Results Among 1,130 pediatric and young adults with radiographically confirmed DIPG, 122 (11%) were excluded. Of the 1,008 remaining patients, 101 (10%) were LTSs (survival ≥ 2 years). Median survival time was 11 months (interquartile range, 7.5 to 16 months), and 1-, 2-, 3-, 4-, and 5-year survival rates were 42.3% (95% CI, 38.1% to 44.1%), 9.6% (95% CI, 7.8% to 11.3%), 4.3% (95% CI, 3.2% to 5.8%), 3.2% (95% CI, 2.4% to 4.6%), and 2.2% (95% CI, 1.4% to 3.4%), respectively. LTSs, compared with STSs, more commonly presented at age < 3 or > 10 years (11% v 3% and 33% v 23%, respectively; P < .001) and with longer symptom duration ( P < .001). STSs, compared with LTSs, more commonly presented with cranial nerve palsy (83% v 73%, respectively; P = .008), ring enhancement (38% v 23%, respectively; P = .007), necrosis (42% v 26%, respectively; P = .009), and extrapontine extension (92% v 86%, respectively; P = .04). LTSs more commonly received systemic therapy at diagnosis (88% v 75% for STSs; P = .005). Biopsies and autopsies were performed in 299 patients (30%) and 77 patients (10%), respectively; 181 tumors (48%) were molecularly characterized. LTSs were more likely to harbor a HIST1H3B mutation (odds ratio, 1.28; 95% CI, 1.1 to 1.5; P = .002). Conclusion We report clinical, radiologic, and molecular factors that correlate with survival in children and young adults with DIPG, which are important for risk stratification in future clinical trials
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Inflation and Dark Energy from spectroscopy at z > 2
The expansion of the Universe is understood to have accelerated during two
epochs: in its very first moments during a period of Inflation and much more
recently, at z < 1, when Dark Energy is hypothesized to drive cosmic
acceleration. The undiscovered mechanisms behind these two epochs represent
some of the most important open problems in fundamental physics. The large
cosmological volume at 2 < z < 5, together with the ability to efficiently
target high- galaxies with known techniques, enables large gains in the
study of Inflation and Dark Energy. A future spectroscopic survey can test the
Gaussianity of the initial conditions up to a factor of ~50 better than our
current bounds, crossing the crucial theoretical threshold of
of order unity that separates single field and
multi-field models. Simultaneously, it can measure the fraction of Dark Energy
at the percent level up to , thus serving as an unprecedented test of
the standard model and opening up a tremendous discovery space
Learning robotic pyeloplasty without simulators: an assessment of the learning curve in the early robotic era
OBJECTIVE: To analyze our experience and learning curve for robotic pyeloplasty during this robotic procedure. METHODS: Ninety-nine patients underwent 100 consecutive procedures. Cases were divided into 4 groups of 25 consecutive procedures to analyze the learning curve. RESULTS: The median anastomosis times were 50.0, 36.8, 34.2 and 29.0 minutes (p=0.137) in the sequential groups, respectively. The median operative times were 144.6, 119.2, 114.5 and 94.6 minutes, with a significant difference between groups 1 and 2 (p=0.015), 1 and 3 (p=0.002), 1 and 4 (po0.001) and 2 and 4 (p=0.022). The mean hospital stay was 7.08, 4.76, 4.88 and 4.20 days, with a difference between groups 1 and 2 (po0.001), 1 and 3 (po0.001) and 1 and 4 (po0.001). Clinical and radiological improvements were observed in 98.9% of patients. One patient presented with recurrent obstruction. CONCLUSIONS: Our results demonstrate a high success rate with low complication rates. A significant decrease in hospital stay and surgical time was evident after 25 cases
Novel Associations between Common Breast Cancer Susceptibility Variants and Risk-Predicting Mammographic Density Measures.
Mammographic density measures adjusted for age and body mass index (BMI) are heritable predictors of breast cancer risk, but few mammographic density-associated genetic variants have been identified. Using data for 10,727 women from two international consortia, we estimated associations between 77 common breast cancer susceptibility variants and absolute dense area, percent dense area and absolute nondense area adjusted for study, age, and BMI using mixed linear modeling. We found strong support for established associations between rs10995190 (in the region of ZNF365), rs2046210 (ESR1), and rs3817198 (LSP1) and adjusted absolute and percent dense areas (all P < 10(-5)). Of 41 recently discovered breast cancer susceptibility variants, associations were found between rs1432679 (EBF1), rs17817449 (MIR1972-2: FTO), rs12710696 (2p24.1), and rs3757318 (ESR1) and adjusted absolute and percent dense areas, respectively. There were associations between rs6001930 (MKL1) and both adjusted absolute dense and nondense areas, and between rs17356907 (NTN4) and adjusted absolute nondense area. Trends in all but two associations were consistent with those for breast cancer risk. Results suggested that 18% of breast cancer susceptibility variants were associated with at least one mammographic density measure. Genetic variants at multiple loci were associated with both breast cancer risk and the mammographic density measures. Further understanding of the underlying mechanisms at these loci could help identify etiologic pathways implicated in how mammographic density predicts breast cancer risk.ABCFS: The Australian Breast Cancer Family Registry (ABCFR; 1992-1995) was supported by
the Australian NHMRC, the New South Wales Cancer Council, and the Victorian Health
Promotion Foundation (Australia), and by grant UM1CA164920 from the USA National
Cancer Institute. The Genetic Epidemiology Laboratory at the University of Melbourne has
also received generous support from Mr B. Hovey and Dr and Mrs R.W. Brown to whom we
are most grateful. The content of this manuscript does not necessarily reflect the views or
policies of the National Cancer Institute or any of the collaborating centers in the Breast
Breast Cancer Susceptibility Variants and Mammographic Density
5
Cancer Family Registry (BCFR), nor does mention of trade names, commercial products, or
organizations imply endorsement by the USA Government or the BCFR.
BBCC: This study was funded in part by the ELAN-Program of the University Hospital
Erlangen; Katharina Heusinger was funded by the ELAN program of the University Hospital
Erlangen. BBCC was supported in part by the ELAN program of the Medical Faculty,
University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nuremberg.
EPIC-Norfolk: This study was funded by research programme grant funding from Cancer
Research UK and the Medical Research Council with additional support from the Stroke
Association, British Heart Foundation, Department of Health, Research into Ageing and
Academy of Medical Sciences.
MCBCS: This study was supported by Public Health Service Grants P50 CA 116201, R01 CA
128931, R01 CA 128931-S01, R01 CA 122340, CCSG P30 CA15083, from the National Cancer
Institute, National Institutes of Health, and Department of Health and Human Services.
MCCS: Melissa C. Southey is a National Health and Medical Research Council Senior
Research Fellow and a Victorian Breast Cancer Research Consortium Group Leader. The
study was supported by the Cancer Council of Victoria and by the Victorian Breast Cancer
Research Consortium.
MEC: National Cancer Institute: R37CA054281, R01CA063464, R01CA085265, R25CA090956,
R01CA132839.
MMHS: This work was supported by grants from the National Cancer Institute, National
Institutes of Health, and Department of Health and Human Services. (R01 CA128931, R01 CA
128931-S01, R01 CA97396, P50 CA116201, and Cancer Center Support Grant P30 CA15083).
Breast Cancer Susceptibility Variants and Mammographic Density
6
NBCS: This study has been supported with grants from Norwegian Research Council
(#183621/S10 and #175240/S10), The Norwegian Cancer Society (PK80108002,
PK60287003), and The Radium Hospital Foundation as well as S-02036 from South Eastern
Norway Regional Health Authority.
NHS: This study was supported by Public Health Service Grants CA131332, CA087969,
CA089393, CA049449, CA98233, CA128931, CA 116201, CA 122340 from the National
Cancer Institute, National Institutes of Health, Department of Health and Human Services.
OOA study was supported by CA122822 and X01 HG005954 from the NIH; Breast Cancer
Research Fund; Elizabeth C. Crosby Research Award, Gladys E. Davis Endowed Fund, and the
Office of the Vice President for Research at the University of Michigan. Genotyping services
for the OOA study were provided by the Center for Inherited Disease Research (CIDR), which
is fully funded through a federal contract from the National Institutes of Health to The Johns
Hopkins University, contract number HHSN268200782096.
OFBCR: This work was supported by grant UM1 CA164920 from the USA National Cancer
Institute. The content of this manuscript does not necessarily reflect the views or policies of
the National Cancer Institute or any of the collaborating centers in the Breast Cancer Family
Registry (BCFR), nor does mention of trade names, commercial products, or organizations
imply endorsement by the USA Government or the BCFR.
SASBAC: The SASBAC study was supported by Märit and Hans Rausing’s Initiative against
Breast Cancer, National Institutes of Health, Susan Komen Foundation and Agency for
Science, Technology and Research of Singapore (A*STAR).
Breast Cancer Susceptibility Variants and Mammographic Density
7
SIBS: SIBS was supported by program grant C1287/A10118 and project grants from Cancer
Research UK (grant numbers C1287/8459).
COGS grant: Collaborative Oncological Gene-environment Study (COGS) that enabled the
genotyping for this study. Funding for the BCAC component is provided by grants from the
EU FP7 programme (COGS) and from Cancer Research UK. Funding for the iCOGS
infrastructure came from: the European Community's Seventh Framework Programme
under grant agreement n° 223175 (HEALTH-F2-2009-223175) (COGS), Cancer Research UK
(C1287/A10118, C1287/A 10710, C12292/A11174, C1281/A12014, C5047/A8384,
C5047/A15007, C5047/A10692), the National Institutes of Health (CA128978) and Post-
Cancer GWAS initiative (1U19 CA148537, 1U19 CA148065 and 1U19 CA148112 - the GAMEON
initiative), the Department of Defence (W81XWH-10-1-0341), the Canadian Institutes of
Health Research (CIHR) for the CIHR Team in Familial Risks of Breast Cancer, Komen
Foundation for the Cure, the Breast Cancer Research Foundation, and the Ovarian Cancer
Research Fund.This is the author accepted manuscript. The final version is available via American Association for Cancer Research at http://cancerres.aacrjournals.org/content/early/2015/04/10/0008-5472.CAN-14-2012.abstract
Hundreds of variants clustered in genomic loci and biological pathways affect human height
Most common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits, but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait. The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (P < 0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways.
Restrictions on pesticides and deliberate self-poisoning in Sri Lanka
Importance Deliberate self-poisoning using pesticides as a means of suicide is an important public health problem in low- and middle-income countries. Three highly toxic pesticides—dimethoate, fenthion, and paraquat—were removed from the market in Sri Lanka between 2008 and 2011. In 2015, less toxic pesticides (chlorpyrifos, glyphosate, carbofuran, and carbaryl) were restricted. Subsequent outcomes have not been well described.Objective To explore the association of pesticide bans with pesticide self-poisonings and in-hospital deaths.Design, Setting, and Participants In this cross-sectional study with an interrupted time series design, data were prospectively collected on all patients with deliberate self-poisonings presenting to 10 Sri Lankan hospitals between March 31, 2002, and December 31, 2019, and analyzed by aggregated types of poisoning. The correlates of pesticide bans were estimated within the pesticide group and on self-poisonings within other substance groups. The data analysis was performed between April 1, 2002, and December 31, 2019.Exposures Implementation of 2 sets of pesticide bans.Main Outcomes and Measures The main outcomes were changes in hospital presentations and in-hospital deaths related to pesticide self-poisoning as measured using segmented Poisson regression.Results A total of 79 780 patients (median [IQR] age, 24 [18-34] years; 50.1% male) with self-poisoning from all causes were admitted to the study hospitals, with 29 389 poisonings (36.8%) due to pesticides. A total of 2859 patients died, 2084 (72.9%) of whom had ingested a pesticide. The first restrictions that targeted acutely toxic, highly hazardous pesticides were associated with an abrupt and sustained decline of the proportion of poisonings with pesticides (rate ratio [RR], 0.85; 95% CI, 0.78-0.92) over the study period and increases in poisonings with medications (RR, 1.11; 95% CI, 1.02-1.21) and household and industrial chemicals (RR, 1.20; 95% CI, 1.05-1.36). The overall case fatality of pesticides significantly decreased (RR, 0.33; 95% CI, 0.26-0.42) following the implementation of the 2008 to 2011 restrictions of highly hazardous pesticides. Following the 2015 restrictions of low-toxicity pesticides, hospitalizations were unchanged, and the number of deaths increased (RR, 1.98; 95% CI, 1.39-2.83).Conclusions and Relevance These findings support the restriction of acutely toxic pesticides in resource-poor countries to help reduce hospitalization for and deaths from deliberate self-poisonings and caution against arbitrary bans of less toxic pesticides while more toxic pesticides remain available
Genome evolution in the allotetraploid frog Xenopus laevis
To explore the origins and consequences of tetraploidy in the African clawed frog, we sequenced the Xenopus laevis genome and compared it to the related diploid X. tropicalis genome. We characterize the allotetraploid origin of X. laevis by partitioning its genome into two homoeologous subgenomes, marked by distinct families of ???fossil??? transposable elements. On the basis of the activity of these elements and the age of hundreds of unitary pseudogenes, we estimate that the two diploid progenitor species diverged around 34 million years ago (Ma) and combined to form an allotetraploid around 17-18 Ma. More than 56% of all genes were retained in two homoeologous copies. Protein function, gene expression, and the amount of conserved flanking sequence all correlate with retention rates. The subgenomes have evolved asymmetrically, with one chromosome set more often preserving the ancestral state and the other experiencing more gene loss, deletion, rearrangement, and reduced gene expression.ope
Identification of new genetic susceptibility loci for breast cancer through consideration of gene-environment interactions
Genes that alter disease risk only in combination with certain environmental exposures may not be detected in genetic association analysis. By using methods accounting for gene-environment (G × E) interaction, we aimed to identify novel genetic loci associated with breast cancer risk. Up to 34,475 cases and 34,786 controls of European ancestry from up to 23 studies in the Breast Cancer Association Consortium were included. Overall, 71,527 single nucleotide polymorphisms (SNPs), enriched for association with breast cancer, were tested for interaction with 10 environmental risk factors using three recently proposed hybrid methods and a joint test of association and interaction. Analyses were adjusted for age, study, population stratification, and confounding factors as applicable. Three SNPs in two independent loci showed statistically significant association: SNPs rs10483028 and rs2242714 in perfect linkage disequilibrium on chromosome 21 and rs12197388 in ARID1B on chromosome 6. While rs12197388 was identified using the joint test with parity and with age at menarche (P-values = 3 × 10(−07)), the variants on chromosome 21 q22.12, which showed interaction with adult body mass index (BMI) in 8,891 postmenopausal women, were identified by all methods applied. SNP rs10483028 was associated with breast cancer in women with a BMI below 25 kg/m(2) (OR = 1.26, 95% CI 1.15–1.38) but not in women with a BMI of 30 kg/m(2) or higher (OR = 0.89, 95% CI 0.72–1.11, P for interaction = 3.2 × 10(−05)). Our findings confirm comparable power of the recent methods for detecting G × E interaction and the utility of using G × E interaction analyses to identify new susceptibility loci
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